Recovery period of the bladder after exposure to soluble virulence factor produced by Escherichia coli

This study was designed to determine the time interval required for the recovery of the bladder after exposure to soluble virulence factor (SVF) in an animal model. In addition, we aimed to determine the changes in the epithelium during the recovery period.

A total of 46 male New Zealand rabbits were used in this study. Sterile human urine was infected with Escherichia coli type O6 to obtain supernatant, which would contain SVF, but no bacteria. Rabbits were assigned to one of three groups comprising the supernatant urine group (SUG) and controls, respectively. Sterile human urine and supernatant urine were instilled to controls and SUG, respectively. Bacterial inoculation with E. coli was performed 1, 24 and 72 h after initial instillation. Histopathologic and microbiologic analyses were performed on these animals.

In SUG bacterial colonization was significantly higher than in controls 1 and 24 h after exposure to supernatant. Histopathologic analysis confirmed this finding. Histologic changes were most pronounced 1 hour after instillation of supernatant. A moderate degree of recovery was noted at 24 h, and complete recovery was seen at 72 h.

Bacterial growth is potentiated by SVF-induced impaired bladder mucosa until the repairing process has been completed. During this time interval, SVF enables the colonization and growth of E. coli and other bacterium species that may result in sustained bacterial presence and recurrent infection.